They have contrasting guitar styles, John Williams being from the classically trained, faultless technique and precision school, while John Etheridge, in a career in jazz and jazz-rock dating back to the 1970s, has thrived on spontaneity and playing right on the edge. Yet rather than finding a compromise, they actually move into each other’s worlds, with Williams ­busking comfortably on Etheridge’s waltz-time Places Between and Etheridge sight-reading and adding his own acoustic sound to the Beethoven-inspired intricacies of the specially composed Ludwig’s Horse.

It’s their pleasure in each other’s company, almost as much as the music itself, that reaches out to their audience. Etheridge probably couldn’t do formality if he tried – he’s exactly the same personality introducing his adventurous, shrewdly electronic solo interpretation of Charles Mingus’s Goodbye Pork Pie Hat as you’d encounter offstage – and Williams isn’t exactly impersonal either. His solo feature, a self-composed piece in four parts, was masterful, particularly in the second movement’s use of harmonic colour combined with ­stunning finger mobility.

Much of their duo repertoire comes from Africa and features nimble re-­imaginings of anthemic songs such as Senegalese singer El Hadj N’Diaye’s Ragajuma and carefully worked transpositions of kora tunes. ­But ­Williams’s composing strengths were apparent again with his dramatically plotted and hugely compelling Extra Time, which brought out authoritative playing from both musicians and was shot through, like everything they played, with genuine warmth.

Star rating: ****